Highway tunnel illumination aims at creating a good light environment for safe and efficient tunnel traffic, ensuring the visibility of the tunnel road surface and the visual ability of the driver, meeting the needs of the driver to quickly get plenty of information from the environment and avoiding traffic accidents caused by lack of visual information. The illumination condition of the tunnel entrance section has a direct effect on the visual characteristics of the driver in daytime. The unreasonable design of lighting level will lead to drastic change of light environment between inside and outside of the tunnel, which causes the “black hole effect” to appear. The driver will suffer from the visual lag phenomenon, resulting in driver's visual recognition difficulty and nervousness. It will lead to wrong driving behavior which tends to induce traffic accidents. For this kind of problem, people at home and abroad put forward various lighting designs of the entrance section in daytime, but there are still some problems.
At home and abroad, there are many problems in the lighting design of the tunnel entrance section in daytime. Only the brightness index is considered, with lack of consideration of light source characteristics such as color temperature and color rendering index. The design index is too simple to meet the actual needs of the driver under various illumination conditions of different light source characteristics such as different color temperatures and different color rendering indexes, which reduces the safety service level of tunnel operation. Static measuring methods are adopted to study the characteristics of the illumination light source and visual recognition of small targets in the tunnel entrance section, and the reliability of the research results is limited. There is still a lack of a reasonable illumination standard test and calculation method for the tunnel entrance section under a certain design speed or under a certain speed limit. In order to improve the safety, stability and comfort, it is needed to find a method and system for measuring and calculating the illumination standard of a tunnel entrance section under various light source characteristics that is able to be used in an actual driving process, especially for a tunnel entrance section in daytime.